Is the Presence of Sn2+ a Crucial Factor for the Generation of Low Thermal Conductivity in Tin-Based Sulfides?
Inorg Chem
; 63(32): 14889-14904, 2024 Aug 12.
Article
en En
| MEDLINE
| ID: mdl-39079026
ABSTRACT
Comprehending the relationship between crystal structures and transport properties is crucial to develop materials with improved electrical and thermal properties for thermoelectric applications. In this article, we report on the complex crystal structure and physical properties of Cr2Sn3S7, a n-type magnetic semiconductor with a low energy band gap and low thermal conductivity. Importantly, we demonstrate that the high level of structural complexity is related to the coexistence of two sublattices a host lattice, [Cr4Sn2S11]2-, characterized by a mixed Sn4+/Cr3+ occupancy of its cationic sites, and a guest lattice characterized by [Sn4S3]2+ chains, containing Sn2+ cations only, closely related to the ones encountered in the orthorhombic SnS compound. By combining experiments including X-ray diffraction with ab initio calculations of electrons and phonons, we succeeded to elucidate the origin of the low thermal conductivity in Cr2Sn3S7. We demonstrate that the low dimensionality of the [Sn4S3]2+ chains, which generates weak Sn···S interactions with the 3D host lattice, is induced by the lone pair stereochemical activity of Sn2+. This lattice softening favors strong anisotropic vibrations at low frequencies, highlighting the primordial role played by Sn2+ cations in both crystal structure dimensionality and low thermal conductivity in tin-based sulfides.
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1
Colección:
01-internacional
Base de datos:
MEDLINE
Idioma:
En
Revista:
Inorg Chem
Año:
2024
Tipo del documento:
Article
País de afiliación:
Francia
Pais de publicación:
Estados Unidos